Non-contact sensor system and method for displacement determination

ABSTRACT

A non-contact sensor system is provided that comprises a first sensor element and a rotary member disposed proximate the first sensor element without physically contacting the first sensor element. The rotary member may be configured to be rotated about an axis Y by a shaft configured to pass through the rotary member along the axis Y at a value X. The non-contact sensor system further comprises a second sensor element disposed on the rotary member proximate the first sensor element without physically contacting the first sensor element, and the first sensor element and the second sensor element may be operatively coupled to facilitate sensing the value X.

FIELD OF THE INVENTION

This invention generally relates to non-contact sensor systems, and moreparticularly, to inductive and capacitive non-contact sensor systems.

BACKGROUND OF THE INVENTION

Various types of sensors are used throughout aircraft to provideinformation about aircraft systems and operating conditions. Due in partto the harsh operating conditions to which aircraft are subjected, thesensors generally should be protected from these operating conditions.Examples of such harsh operating conditions are high shock, highvibration, high and low temperature extremes, humidity, wetness, dust,snow, and ice. These harsh operating conditions are further exacerbatedby the high velocity at which aircraft travel. To account for theseoperating conditions, aircraft sensors are generally robustlyconstructed, often resulting in increased expense and weight. It istherefore desirable to reduce the cost and weight of such sensorswithout unacceptable loss in accuracy.

Additionally, many aircraft sensors have touching and/or moving parts.Contacts in the sensors that require physical connections for operationmay wear out and become unreliable. Replacing these already expensivesensors results in even greater expense.

In other industries, non-contact sensors have been employed in responseto some of the concerns associated with contact-based sensors. Becauseof factors such as those noted above, these non-contact sensors have notgenerally been used to replace contact-based sensors in aircraft.Instead, some prior aircraft brake wear systems have generally usedvisual inspection of a wear pin to determine the degree of brake wearthat has occurred. Several disadvantages to visual inspection exist,including accuracy and timing of inspection. Thus, it is desirable toimprove the accuracy of measurement and the timing of inspection.

SUMMARY OF THE INVENTION

A non-contact sensor system comprises, in one embodiment, a first sensorelement and a rotary member disposed proximate the first sensor elementwithout physically contacting the first sensor element. The rotarymember may be configured to be rotated about an axis Y by a shaftconfigured to pass through the rotary member along the axis Y at a valueX. The non-contact sensor system may further comprise a second sensorelement disposed on the rotary member proximate the first sensor elementwithout physically contacting the first sensor element, and the firstsensor element and the second sensor element may be operatively coupledto facilitate sensing the value X.

In some embodiments, a control unit for an aircraft non-contact sensorsystem comprises a signal generator configured to produce a current in afirst sensor element. The first sensor element may be operativelycoupled to a second sensor element without physically contacting thesecond sensor element. In an embodiment, the control unit furthercomprises a calculator configured to determine a value X in response toa determination of a value Z associated with a rotary member disposedproximate the first sensor element. The rotary member is configured tobe rotated about an axis Y by a shaft configured to pass through therotary member along the axis Y at the value X, and the value Z isassociated with the rotation of the rotary member about the axis Y.

Further, according to various embodiments, a computer readable mediummay have stored thereon a plurality of instructions comprisinginstructions to generate a signal that causes a first current to flow inan electrical circuit in a first non-contact sensor element. A firstelectromagnetic field is generated in response to the signal, and thefirst non-contact sensor element is disposed proximate a secondnon-contact sensor element without physically contacting the secondnon-contact sensor element. The instructions may further compriseinstructions to sense a second electromagnetic field by a sensingcircuit in the first non-contact sensor element, the secondelectromagnetic field being generated in response to a second currentflowing through a resonant circuit on the second non-contact sensorelement. The second current is generated in response to the firstelectromagnetic field and the second non-contact sensor element isdisposed on a rotary member that is configured to be rotated about anaxis Y by a shaft configured to pass through the rotary member along theaxis Y at a value X. The instructions may further comprise instructionsto determine the value X in response to sensing the secondelectromagnetic field and in response to a value Z associated with therotation of the rotary member about the axis Y.

Additionally, various embodiments provide a non-contact sensor systemthat comprises a first sensor element disposed within a first memberhaving an axis Y, and a second member configured to rotate about theaxis Y at a value X, wherein the second member is configured tointerface with the first member. The non-contact sensor system mayfurther comprise a second sensor element disposed on the second memberproximate the first sensor element, without physically contacting thefirst sensor element, and the first sensor element and the second sensorelement may be operatively coupled to facilitate sensing the value X.

Furthermore, various embodiments may provide a non-contact sensor systemthat comprises a first sensor element disposed on an outside surface ofa chamber having an inside surface that is configured to receive apiston, the piston being configured to move a value X within thechamber, without physically contacting the first sensor element. Thenon-contact sensor system may further comprise a second sensor elementdisposed on the piston and separated by a wall of the chamber, and thefirst sensor element and the second sensor element being operativelycoupled to facilitate sensing the value X.

Moreover, in accordance with various embodiments, a non-contact sensorsystem may comprise a first sensor element disposed on a stationarymember, and a second sensor element disposed on a rotational member. Thesecond sensor element is proximate the first sensor element, withoutphysically contacting the first sensor element, and the rotationalmember is configured to facilitate selection of at least a firstposition and a second position. In such embodiments, the first sensorelement and the second sensor element are operatively coupled tofacilitate sensing of the selected position.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 illustrates a perspective view of a non-contact sensor system formeasuring brake wear according to an embodiment;

FIG. 2 illustrates a perspective view of a second non-contact sensorsystem for measuring brake wear according to an embodiment;

FIG. 3 illustrates a cross-sectional view of a rotational member for usein a non-contact sensor system according to an embodiment;

FIG. 4 illustrates a cross-sectional view of a non-contact sensor systemfor measuring wheel rotation according to an embodiment;

FIG. 5 illustrates a cross-sectional view of a second non-contact sensorsystem for measuring wheel rotation according to an embodiment;

FIG. 6 illustrates a cross-sectional view of a non-contact sensor systemfor use with a pedal sensor according to various embodiments;

FIG. 7 illustrates a perspective view of a non-contact sensor system foruse with an autobrake switch according to an embodiment; and

FIG. 8 illustrates a cross-sectional view of a non-contact sensor systemfor use with a hydraulic accumulator according to an embodiment.

DETAILED DESCRIPTION

The detailed description of various embodiments herein makes referenceto the accompanying drawing figures, which show various embodiments andimplementations thereof by way of illustration and its best mode, andnot of limitation. While these embodiments are described in sufficientdetail to enable those skilled in the art to practice the embodiments,it should be understood that other embodiments may be realized and thatlogical, electrical, and mechanical changes may be made withoutdeparting from the spirit and scope of the invention. For example, thesteps recited in any of the method or process descriptions may beexecuted in any order and are not necessarily limited to the orderpresented. Moreover, many of the functions or steps may be outsourced toor performed by one or more third parties. Furthermore, any reference tosingular includes plural embodiments, and any reference to more than onecomponent or step may include a singular embodiment or step. Also, anyreference to attached, fixed, connected or the like may includepermanent, removable, temporary, partial, full and/or any other possibleattachment option. Additionally, any reference to without contact (orsimilar phrases) may also include reduced contact or minimal contact.

Various embodiments provide a non-contact sensor system that comprises afirst sensor element operatively coupled to a second sensor elementwithout physically contacting the second sensor element. For example,the non-contact sensor system may use electromagnetism, magnetism,induction, and/or capacitance to create and/or modify an electromagneticfield between the first sensor element and the second sensor element inorder to cause current to flow in the first sensor element and/or thesecond sensor element, without any physical connections between thefirst sensor element and the second sensor element. In variousembodiments, any method of causing current to flow in the second sensorelement in response to a current flowing in the first sensor elementwhere the first sensor element does not physically contact the secondsensor element is contemplated and within the scope of the presentdisclosure. Similarly, any sensor system configured to calculateposition information based on a relative location of a first sensorelement to a second sensor element, where the first and second sensorelements are not in physical contact with each other, is contemplatedwithin the scope of the present disclosure.

The first sensor element, in various embodiments, comprises anelectrical circuit that may be disposed, for example, on a printedcircuit board that includes at least one electrically conductive track,coil, circuit element or the like. Further the electrical circuit maycomprise standard electronic components not embodied on a printedcircuit board and/or the electrical circuit may comprise an integratedcircuit. The electrical circuit may comprise a plurality of circuits,such as an excitation circuit, a sensing circuit, or the like. At leasta portion of the electrical circuit, for example, an excitation circuit,is configured to carry an excitation signal that in turn generates afirst electromagnetic field. It should be noted that in variousembodiments, the electrical circuit and/or portions thereof may belocated in one place in the sensor system, or they may be located inseparate places. For example, the excitation circuit may be located inone location, and the sensing circuit may be located in a separatelocation. The first electromagnetic field generated by the electricalcircuit of the first sensor element is configured to induce a resonantcurrent in a resonant circuit disposed on the second sensor element. Theresonant current induced in the resonant circuit is configured togenerate a second electromagnetic field, and the second electromagneticfield is configured to induce a sensing current in a sensing circuitthat is part of the electrical circuit on the first sensor element. Theelectromagnetic coupling between the first sensor element and the secondsensor element is configured to vary with the relative position of thesecond sensor element to the first sensor element, and the sensingcurrent may thus be used to determine the relative position of thesecond sensor element to the first sensor element.

As noted above with respect to the first sensor element, in accordancewith various embodiments, it should be understood that the first sensorelement and the second sensor element may individually comprise aplurality of sensor elements. For example, the first sensor element maycomprise two or more sensor elements, and/or the second sensor elementmay comprise two or more sensor elements. These sensor elements may bemounted respectively on a fixed member and a moveable member. In variousembodiments, the fixed member and the moveable member may compriseactive portions, for example, where the sensor elements are located, andthey may comprise inactive portions, for example, where the sensorelements are not located. Various embodiments further comprise sensorsystems where the fixed member and the moveable member may comprise onlyactive portions, such that the fixed member is the first sensor elementand the movable member is the second sensor element. Thus it should beunderstood that while various embodiments may be described with a sensorelement being disposed on a fixed and/or movable member, in variousembodiments the fixed and/or movable member may not be present, or thefirst sensor element and/or second sensor element may be present in thesensor system without being disposed on a fixed member and/or a movablemember. Further, it should be understood that while various embodimentsmay be disclosed as comprising single sensor elements, these sensorelements may comprise multiple sensor elements without departing fromthe scope of the invention. It should further be understood that anyelectrical circuit, now known or hereafter developed, that is capable ofproviding the functionality disclosed herein is contemplated within thescope of this disclosure.

According to various embodiments, a control unit may be used to generatethe excitation signal. The control unit may further be configured toreceive the sensing signal and perform signal conditioning operations todetermine the relative position of the second sensor element to thefirst sensor element. As will be discussed further below, the controlunit may also be configured to determine a value associated with anaircraft system in response to the relative position of the secondsensor element to the first sensor element. A separate control unit maybe used for each combination of the first sensor element and the secondsensor element, or a single control unit may be used to determine aplurality of values associated with a plurality of aircraft systems inconjunction with a plurality of first and second sensor elementcombinations.

An aircraft brake wear measurement system, according to an embodiment,is configured to determine how much an aircraft brake has worn. Thebreak wear is determined by measuring the displacement between thebrake's pressure plate (which includes the brake wear sensor's referencepoint) and a piston housing. A wear pin is attached to the pressureplate and passes through a rotational member that comprises a secondnon-contact sensor element. The wear pin's geometry is configured torotate the rotational member as the wear pin moves linearly with thepressure plate. The rotation of the rotational member is proportional tothe linear movement of the brake's pressure plate.

With reference to FIGS. 1 and 2, a brake wear non-contact sensor system10 according to an embodiment is configured to determine a distancetraveled by a wear pin 12. Wear pin 12 is attached to a brake systempressure plate 11 that is configured to exert a controllable brakingforce on a brake stack. As the brake stack wears, the distance betweenpressure plate 11 and brake housing 13 increases.

Brake wear non-contact sensor system 10 further comprises a wear sensor14 configured to be attached to brake housing 13. As illustrated in FIG.2, wear pin 12 is configured to pass through brake housing 13, or, asillustrated in FIG. 1, wear pin 12 does not pass through brake housing13. With momentary reference to FIG. 3, wear sensor 14 comprises arotational member 15 configured to interface with wear pin 12, arotational sensor element 16 disposed on rotational member 15, and afixed sensor element 17 disposed proximate rotational sensor element 16without physically contacting rotational sensor element 16 or rotationalmember 15. Fixed sensor element 17 is coupled via connector 18 to acontrol unit (not shown) that is configured to provide an excitationsignal to fixed sensor element 17.

As the brake stack begins to wear, pressure plate 11 moves further frombrake housing 13, and wear pin 12 is configured to cause rotationalmember 15 to rotate a rotational distance Z about an axis Y along whichwear pin 12 is oriented. With momentary reference to FIG. 3, andaccording to various embodiments, wear pin 12 may comprise a helix 19,groove, flute, channel or the like that is configured to interface witha key 9 in rotational member 15. Such an interaction may be configuredto convert the linear movement of wear pin 12 into a rotational movementof rotational member 15 about the axis Y. As rotational member 15rotates, the relative position of rotational sensor element 16 to fixedsensor element 17 changes.

In accordance with an embodiment where fixed sensor element 17 comprisesa printed circuit board, the control unit causes an excitation signal toflow through an excitation circuit, such as an excitation coil (e.g., anantenna included in a printed circuit board) in fixed sensor element 17.The excitation signal then causes a first electromagnetic field to formin response to the excitation signal flowing through the excitationcoil. This first electromagnetic field is configured to be at a resonantfrequency of rotational sensor element 16, and induces a current inrotational sensor element 16. This induced current in rotational sensorelement 16 is configured to generate a second electromagnetic field, andthe second electromagnetic field in turn is configured to induce acurrent in a sensing circuit, such as a sensing coil in fixed sensorelement 17. This current is sensed by the control unit via connector 18,and the current is used to determine the relative position of fixedsensor element 17 to rotational sensor element 16. The relative positionis then used to determine the rotational distance Z traveled byrotational sensor element 16 on rotational member 15. The amount ofrotation is proportional to a linear distance X traveled by wear pin 12,and the control unit therefore is configured to determine the lineardistance X traveled by wear pin 12 and the brake wear associated withlinear distance X.

In accordance with various embodiments, rotational sensor element 16 maybe located on one or more portions of rotational member 15. For example,rotational sensor element 16 may comprise a plurality of sensor elementsdisposed about the circumference of rotational member 15. Rotationalsensor element 16 may further be disposed continuously about thecircumference of rotational member 15. Further, various embodiments mayprovide that rotational sensor element 16 is configured to rotate aboutthe axis Y without being disposed on rotational member 15, or rotationalmember 15 and rotational sensor element 16 may be configured to be thesame component.

With reference to FIGS. 4 and 5, a non-contact wheel speed sensor system20 according to an embodiment comprises a fixed sensor element 27disposed within a wheel axle 21 configured to interface with a wheel hub23. Wheel hub 23 is configured to rotate about an axis Y, and wheel axle21 is configured to be aligned with the axis Y.

As illustrated in FIG. 4, a fixed sensor element 27 comprises adisk-shaped electrical circuit, for example, a disk-shaped electricalcircuit board configured to be disposed across wheel axle 21, such thata vector normal to fixed sensor element 27 at any point is substantiallyparallel to axis 29 of wheel hub 23. In various configurations, wheelhub 23 comprises a rotational sensor element 26 has a normal vectorsubstantially parallel to axis 29. Thus, in response to wheel hub 23being engaged with axle 21, the sensing surfaces of fixed sensor element27 and rotational sensor element 26 are substantially parallel to eachother.

As illustrated in FIG. 5, fixed sensor element 27 comprises anelectrical circuit, for example, a flexible flat circuit board disposedcircumferentially against a wall of wheel axle 21 and about axis 29 ofwheel hub 23. In such a configuration, wheel hub 23 comprises arotational sensor element 26 that is disposed circumferentially againsta wall of wheel hub 23 and about axis 29. Thus, in response to wheel hub23 being engaged with wheel axle 21, the sensing surfaces of fixedsensor element 27 and rotational sensor element 26 are substantiallyequidistant from each other over the sensing surfaces. It should beunderstood that fixed sensor element 27 may comprise a plurality offixed sensor elements disposed within wheel axle 21, and/or thatrotational sensor element 26 may comprise a plurality of rotationalsensor elements disposed on wheel hub 23.

With reference to both FIGS. 4 and 5, in various embodiments, thecontrol unit is configured to cause an excitation signal to flow throughan excitation circuit such as an excitation coil in fixed sensor element27. The excitation signal may then be configured to cause a firstelectromagnetic field to form in response to the excitation signalflowing through the excitation coil. This first electromagnetic field isconfigured to be at a resonant frequency of rotational sensor element26, and is configured to induce a current in rotational sensor element26. This induced current in rotational sensor element 26 generates asecond electromagnetic field, and the second electromagnetic field inturn induces a current in a sensing circuit, such as a sensing coil infixed sensor element 27.

This current may then be sensed by the control unit via connector 28,and the current may be used to determine the relative position of fixedsensor element 27 to rotational sensor element 26 in order to determinea value X associated with the relative position about the axis Y. Therelative position may thus used to determine the amount of rotation ofwheel hub 23. Repeated position measurements may be used to determine avelocity and/or acceleration of wheel hub 23 about axis 29.

According to various embodiments, and with reference to FIG. 6, anon-contact pedal sensor is configured to determine the position of apedal, for example, as used in an aircraft. FIG. 6 illustrates twonon-contact pedal sensors 30, 40. It should be understood that invarious embodiments, both non-contact pedal sensors 30, 40 may bepresent, or only one of non-contact pedal sensor 30 or non-contact pedalsensor 40 may be present. Both non-contact pedal sensors 30, 40 areillustrated in FIG. 6 for purposes of illustration and description of anembodiment.

In such embodiments, as the pedal moves, a piston assembly 41 isconfigured to move a distance X within a chamber 31, and a spring 32 isconfigured to maintain piston assembly 41 in a starting position if aforce is not exerted on piston assembly 41. The relative position ofpiston assembly 41 within chamber 31 is used to determine a position ofthe aircraft pedal.

With continued reference to FIG. 6, in various embodiments, pistonassembly 41 comprises a first sensor element, such as magnet 36 disposedon a piston head 35. On the outside of chamber 31, a fixed sensorelement 37 is disposed over a distance sufficient to cover the totaltravel distance of piston head 35. Chamber 31 separates magnet 36 andfixed sensor element 37. Magnet 36 is configured to produce aelectromagnetic field, and as piston assembly 41 moves, theelectromagnetic field induces a current in a sensing circuit such as asensing coil in fixed sensor element 46. The current induced may thus beused by the control unit, via transmission by connector 38, to determinea distance X traveled by piston head 35 and thus a relative position ofpiston head 35 to fixed sensor element 37 in order to determine theposition of the aircraft pedal. It should be understood that while amagnet is disclosed, various embodiments of the invention comprise asecond sensor element instead of a magnet, where the second sensorelement is configured to be an active sensor element, such as a resonantcircuit disclosed in other embodiments, and may be operatively coupledto the first sensor element via induction, capacitance, or the like.

In various embodiments, and with continued reference to FIG. 6, pistonassembly 41 may comprise a piston shaft 42 that is configured to rotatea rotational member 47 about an axis Y in a manner similar to therotation of rotational member 15 by wear pin 12 (discussed above). Afixed sensor element 46 is positioned on a fixed member 45 that issubstantially parallel to rotational member 47. A rotational sensorelement 48 is disposed on rotational member 47 without physicallycontacting fixed member 45 or fixed sensor element 46. As noted above,in various embodiments, fixed sensor element 46 may be disposed on onlya portion of fixed member 45, fixed sensor element 46 may be configuredto operate without fixed member 45, or fixed sensor element 46 may notbe disposed on fixed member 45. Further, in various embodiments,rotational sensor element 48 may be disposed on only a portion ofrotational member 47, or rotational sensor element 48 may be configuredto operate without rotational member 47 (e.g., where rotational sensorelement 48 is present in the sensor system without rotational member47). According to various embodiments, the sensor system may comprisefixed sensor element 46 and/or rotational sensor element 48 withoutcomprising fixed member 45 and/or rotational member 47.

The control unit, in accordance with various embodiments, is configuredto cause an excitation signal to flow through an excitation circuit suchas an excitation coil in fixed sensor element 46. The excitation signalcauses a first electromagnetic field to form in response to theexcitation signal flowing through the excitation coil. This firstelectromagnetic field is configured to be at a resonant frequency ofrotational sensor element 48, and induces a current in rotational sensorelement 48. This induced current in rotational sensor element 48generates a second electromagnetic field, and the second electromagneticfield in turn induces a current in a sensing circuit (e.g., a sensingcoil) in fixed sensor element 46.

This current is sensed by the control unit via connector 48, and is usedto determine the relative position of fixed sensor element 46 torotational sensor element 48. This relative position is used todetermine the amount of rotation of rotational member 47. The amount ofrotation is proportional to a linear distance X traveled by pistonassembly 41, and the control unit therefore determines the lineardistance X traveled by piston assembly 41 and the pedal positionassociated with that linear distance.

With reference now to FIG. 7, an autobrake switch sensor 50 according toan embodiment is disclosed. Autobrake switch sensor 50 is configured todetermine a position of knob 51, and knob 51 is configured to select aplurality of options. Knob 51 is configured to turn the autobrake off,and it is configured to select “LO,” “MED,” “HI,” “MAX,” or “RTO”options in connection with the autobrake.

It should be understood that in various embodiments, any number ofselections may be made by a selection sensor. For example, knob 51 maybe configured to select between two options, such as “ON” and “OFF.”Knob 51 may further be configured to select between ten, or twenty, ormore options. In accordance with various embodiments, a sensor may beconfigured to utilize a reconfigurable switch plate display 63, suchthat the sensor may be configured to sense two options with one switchplate display, and the sensor may be configured to sense more than twooptions in another switch plate display.

To facilitate sensing the selection, according to various embodiments,autobrake switch sensor 50 comprises a fixed sensor element 57 disposedproximate a rotational member 56 without physically contactingrotational member 56. Rotational member 56 comprises a rotational sensorelement 59 that does not physically contact fixed sensor element 57.Rotational member 56 is configured to be connected to knob 51 withswitch plate display 63 located between knob 51 and rotational member56, such that when knob 51 rotates, rotational member 56 rotates, butswitch plate display 63 remains stationary.

In an embodiment, autobrake switch sensor 50 is configured to sense arelative position of rotational sensor element 59 to fixed sensorelement 57 and thereby determine the selection indicated by the positionof knob 51 and rotational member 56. The control unit is configured tocause an excitation signal to flow through an excitation circuit such asan excitation coil in fixed sensor element 57. The excitation signalcauses a first electromagnetic field to form in response to theexcitation signal flowing through the excitation coil. This firstelectromagnetic field is configured to be at a resonant frequency ofrotational sensor element 59 and to induce a current in rotationalsensor element 59. This induced current in rotational sensor element 59generates a second electromagnetic field, and the second electromagneticfield in turn induces a current in a sensing circuit (e.g., a sensingcoil) in fixed sensor element 57. This current is sensed by the controlunit via connector 58, and the current is used to determine the relativeposition of fixed sensor element 57 to rotational sensor element 59. Therelative position is then used to determine the selection indicated byknob 51 and rotational member 56. It should be noted that in variousembodiments, fixed sensor element 57 may be disposed on at least aportion of a fixed member. Further, according to various embodiments,rotational sensor element 59 may comprise a plurality of rotationalsensor elements disposed on rotational member 56, or rotational sensorelement 59 may function without rotational member 56, where rotationalmember 56 is not included as part of the sensor system.

In accordance with various embodiments, knob 51 may be configured toactuate fixed sensor element 57, rotational sensor element 59, and/orthe control unit. For example, knob 51 may be rotated to a desiredposition, and then knob 51 may be pressed, pulled, and/or otherwiseactuated to facilitate activating the sensor system. In response to knob51 being pressed and/or pulled, for example, a current may be configuredto flow through the excitation circuit in fixed sensor element 57.

In various embodiments, and with reference to FIG. 8, a hydraulicaccumulator volume sensor system 60 is configured to determine an amountof available hydraulic fluid in hydraulic accumulator 61. A piston 62 isdisposed in hydraulic accumulator 61, and is configured to separate afirst section 64 from a second section 65. In an embodiment, firstsection 64 is configured to be filled with nitrogen, and second section65 is configured to be filled with hydraulic fluid. As hydraulic fluidis utilized in an aircraft, the amount (e.g., a volume, weight,pressure, etc.) of hydraulic fluid available in hydraulic accumulator 61is reduced, and piston 62 may move a distance X within accumulator 61.Determining the position of piston 62 within hydraulic accumulator 61facilitates determination of the amount of hydraulic fluid available. Invarious embodiments, hydraulic volume sensor system 60 may be configuredto be used within pressure-bearing vessels to facilitate sensing avolume within the pressure-bearing vessels.

Hydraulic accumulator volume sensor system 60 comprises a magnet 66disposed on piston 62 proximate a wall of hydraulic accumulator 61. Asnoted previously, although a magnet is disclosed, it should beunderstood that various non-contact sensors described herein may beemployed in addition to and/or instead of magnet 66. Hydraulicaccumulator volume sensor system 60 further comprises a fixed sensorelement 67 disposed outside of hydraulic accumulator 61 over a distancesufficient to cover the total travel distance of piston 62. Hydraulicaccumulator 61 physically separates magnet 66 and fixed sensor element67. Magnet 66 is configured to produce a electromagnetic field, and aspiston 62 moves, the electromagnetic field is configured to induce acurrent in a sensing circuit (e.g., sensing coil) in fixed sensorelement 67. The current induced is used by the control unit, viatransmission by connector 68, to determine a relative position of piston62 to fixed sensor element 67 and thereby facilitate determination ofthe available hydraulic fluid within hydraulic accumulator 61.

In various embodiments, the control unit may comprise a processorconfigured to control the various operations disclosed herein. Suchprocessors are known in the art, and any processor now known orhereafter developed may be used to facilitate control of the controlunit. Additionally, the control unit may further comprise a computerreadable medium configured to provide instructions to the processor forcarrying out the various operations disclosed herein. The computerreadable medium may be embodied in any form readable by the processorthat is now known or hereafter developed. Examples of such computerreadable media are flash memory, solid state memory, magnetic discs(e.g., hard disks, floppy discs, and the like), and optical discs (e.g.,compact discs, digital versatile discs, Blu-Ray discs, and the like).

The control unit, electronic circuits, integrated circuits, and the likedisclosed herein, and in accordance with various embodiments, maycomprise any electronic circuit configured to control the variousoperations disclosed herein. The electronic circuit may comprise anyknown electronic components (for example, transistors, capacitors,diodes, resistors, and the like) configured to perform the variouscalculations and/or determinations to determine position, displacement,velocity, acceleration, and the like, relating to the sensor elementsand sensor systems disclosed herein. Such calculations may be performedand/or carried out with or without a general-purpose processor,software, or a computer readable medium. Such calculations may beperformed and/or carried out with or without the use of an integratedcircuit. It should be understood that any method for determining thevarious characteristics, outputs, readings, measurements, and the like,associated with the sensor elements and sensor systems disclosed herein,whether now known or hereafter developed, is contemplated within thescope of the present disclosure. For example, the various circuitsdisclosed herein may be configured to provide analog and/or digitalsignals (e.g., digital pulse output from the fixed sensor element to thecontrol unit) for processing by the control unit.

Although various embodiments for a non-contact sensor system have beendisclosed, it should be understood that the present disclosure is notlimited to such applications. Various modifications will be apparent toone skilled in the art in order to adapt the non-contact sensor systemdisclosed herein to other applications, and such other applications arethus contemplated within the scope of the present disclosure.

In various embodiments, it may be desirable to determine a value X, suchas a linear position of an object. For example, a shaft may be attachedto the object, and as the object moves, the shaft causes a rotationalmember to rotate about an axis Y. One non-contact sensor element asdisclosed herein may be attached to the rotational member, and anothernon-contact sensor element may be located proximate to the firstnon-contact sensor element without physically contacting the firstnon-contact sensor element. In various embodiments, the rotationalsensor element and/or the fixed sensor element may be configured tofunction without the rotational member and/or the fixed member. Usingthe electromagnetism, capacitance, and/or induction principles discussedherein, a linear position of the object may be determined by determiningthe amount of rotation of the rotational member and a correspondingrotational distance Z traveled by the second non-contact sensor element.In some circumstances, it may also be desirable to determine the degreeof rotation of the rotational member, or other rotating object, apartfrom a linear position of the object mentioned above.

Linear position of an object according to various embodiments may alsobe determined by affixing a magnet to a portion of the object or anelement associated with the object. A non-contact sensor disclosedherein may then be positioned proximate the magnet without physicallycontacting the magnet. As the magnet moves with the object movement, theprinciples disclosed herein associated with the non-contact sensorelement may be used to determine the relative position of the magnet tothe non-contact sensor element, and thus be used to determine the linearposition of the object.

In accordance with various embodiments, only one linear or rotationalposition is determined, though it should be understood that any numberof calculations and/or values relating to the position determination maybe determined in accordance with physical principles. For example,repeated linear position measurements may be used to determine linearvelocity and/or linear acceleration of an object. Repeated rotationalposition measurements may be used to determine rotational velocityand/or rotational acceleration of an object. A volume, weight, mass,pressure, or the like determination may also be made where a linearposition measurement indicates the position of a piston within acylinder or other body. One skilled in the art will appreciate that anynumber of calculations and/or determinations may be made in accordancewith principles disclosed herein.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to various embodiments. However, thebenefits, advantages, solutions to problems, and any elements that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as critical, required, or essentialfeatures or elements of the invention. The scope of the invention isaccordingly to be limited by nothing other than the appended claims, inwhich reference to an element in the singular is not intended to mean“one and only one” unless explicitly so stated, but rather “one ormore.” Moreover, where a phrase similar to “at least one of A, B, and C”is used in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C. Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is to be construed under theprovisions of 35 U.S.C. 112, sixth paragraph, unless the element isexpressly recited using the phrase “means for.” As used herein, theterms “comprises”, “comprising”, or any other variation thereof, areintended to cover a non-exclusive inclusion, such that a process,method, article, or apparatus that comprises a list of elements does notinclude only those elements but may include other elements not expresslylisted or inherent to such process, method, article, or apparatus.

1. A non-contact sensor system, comprising: a first sensor element; arotary member disposed proximate the first sensor element withoutphysically contacting the first sensor element, wherein the rotarymember is configured to be rotated about an axis Y by a shaft configuredto pass through the rotary member along the axis Y; and a second sensorelement disposed on the rotary member proximate the first sensor elementwithout physically contacting the first sensor element, wherein thefirst sensor element and the second sensor element are operativelycoupled to facilitate sensing a displacement value X, wherein thedisplacement value X represents displacement parallel with the axis Y,wherein the rotary member is configured to interface with a wear pin,and wherein the wear pin comprises a channel configured to facilitaterotation of the rotary member about the axis Y, in response to the wearpin moving through the rotary member along the axis Y.
 2. Thenon-contact sensor system of claim 1, wherein the displacement value Xincludes a wear distance configured to indicate a degree of wear of abreak pad in a brake system.
 3. The non-contact sensor system of claim1, wherein the first sensor element comprises an integrated circuit. 4.The non-contact sensor system of claim 1, wherein the first sensorelement and the second sensor element are inductively coupled tofacilitate sensing the displacement value X.
 5. The non-contact sensorsystem of claim 1, wherein the first sensor element includes anelectrical circuit, and wherein the first sensor element is configuredto induce a current in the second sensor element in response to acurrent in the electrical circuit.
 6. The non-contact sensor system ofclaim 1, wherein the second sensor element is configured to induce acurrent in the first sensor element in response to the first sensorelement inducing a current in the second sensor element.
 7. Thenon-contact sensor system of claim 1, wherein the displacement value Xis determined in response to the second sensor element inducing acurrent in the first sensor element.
 8. The non-contact sensor system ofclaim 1, wherein first sensor element and the second sensor element arecoupled in a capacitive manner to facilitate sensing the displacementvalue X.
 9. The non-contact sensor system of claim 2, wherein the wearpin is attached to a pressure plate that is configured to facilitate useof the brake pad.
 10. The non-contact sensor system of claim 9, whereinthe brake pad includes a plurality of brake pads.
 11. The non-contactsensor system of claim 9, wherein the wear pin passes through a brakehousing.
 12. The non-contact sensor system of claim 1, wherein firstsensor element is positioned normal to the axis Y, and wherein thedisplacement value X is configured to be determined in response to adistance traveled by the second sensor about the axis Y.
 13. Thenon-contact sensor system of claim 1, wherein the non-contact sensorsystem is configured to measure a distance traveled by a pedal, andwherein the displacement value X includes the distance traveled by thepedal.
 14. The non-contact sensor system of claim 13, further comprisinga piston disposed within a chamber, wherein the piston is configured tofacilitate determining the distance traveled by the pedal.
 15. Thenon-contact sensor system of claim 14, wherein the rotary member isdisposed within the chamber, wherein the first sensor element isdisposed in the chamber and proximate to the rotary member, and whereinthe first sensor is positioned substantially parallel to the rotarymember.